1. Field of the Invention
This invention relates to face seal shut-off valves and more specifically to a face seal shut-off valve which is integral to a conduit connection.
2. Description of the Prior Art
Many industries, such as the semiconductor industry, require high purity gas in their processes. Impurities such as moisture and particles in the gas can cause defective products. In order to remove these impurities from the gas, various filters and purifiers are located along the gas lines.
The filters and purifiers have limited life spans and must be replaced periodically. These filters and purifiers have an inlet and outlet port connected to the gas line. Each inlet and outlet port has a separate connector and a separate manual shut-off valve. In order to remove and change a filter or purifier, the manual shut-off valves at each end are closed. This prevents atmospheric gas and contaminants from entering the gas line system. Additionally, some purifiers are damaged by exposure to the atmosphere. These purifiers are also isolated by means of valves prior to installation or removal. Thus, after the shut-off valves are closed, the connections on each side are then loosened and the filter or purifier is removed and replaced with a new one.
A problem with these prior art systems is that each of the valves and connectors have a relatively large volume inside which allows in atmospheric gases and other impurities during the replacement operation. Such volumes have surface areas associated with them that provide adhesion surfaces for contamination, particularly moisture. Thus, when the system is reactivated, these impurities are present in the system. There is a need to reduce these entrapment volumes in order to maintain the high purity level of the system.